Mapping the human genome by linkage analysis using highly polymorphic sequences of DNA has led to the establishment genetic loci for a number of illnesses. Although there is suggestive evidence for a genetic risk factor in schizophrenia, attempts to establish linkage have not yet been successful. Part of the problem may have been the lack of a proper phenotype. The use of neurobiological parameters, in addition to diagnosis, for phenotyping is discussed in Project 1. A second part of the problem is the lack of sufficient variation in alleles at informative sites. The introduction of restriction fragment length polymorphisms, including variable number of tandem repeats of DNA sequences (VNTR) as alleles greatly increases the polymorphisms at many sites throughout the genome. We will employ the technology to genotype schizophrenia in large pedigrees recruited from-religious communities in Utah.